Cement-burning apparatus.



H. L. DOHERTY. UEMENT BURNING APPARATUS. APBLIOATiON FILED NOV. 14, 1905.

Patented Apr. 13, 1909.

wi imcmec i zlm/zzajaad HENRY L. DOHERTY, ornnw roan-u. r,

Assienon To ooneusrren u'rrarrins' rem, erN-aw roan-,1, A eoaronnrron or n nwrcnn.

cement-sesame nrrnnarns.

No. 918,020! specificationofl Letters Patent. 1emerited earn a ena.

Appn auen'meamtenber l 4,-19ii5. 'senn ne. ease.

To all whom a may amm- A Be a known that 1, Hnn'nrL. Don'nnr'r,

* a citizen of the United'State-s, and a resident of New York, in the county of NewYei-k and State of New York, haveinven'ted certa'in new and useful Improvements in Ge- "m'ent-Burning Apparatus, of Iwhich'the following is a specification.

' This invention relates to apparatus for burning'cement byfmeans of 'pro'clucer gas, and has for its. object the combustion ofthe gas with preheated air under conditions which permit of the attainment of the very high temperature necessary for the effective and rapid clinkering -'of cementitious 'm'aterial.

In the eiforts which have been made in the past to burn cement'with producer gas m'o'st investigators have overlooked the important fact that air at a high temperature is necessary -for creating the requisite flame temperature of the gas undergoing" corn:

bustion in the cement kiln. If coldair is used for this'purpose, a flame temperature rarely exceeding 2200 is obtained. Inasmuch as the clinkering temperatures range between 2500 and 3000 R, such amethod of procedurehas been ine'liectual. By pre'- heating the air it is possible to secure the temperature desired, but preheating cannot be attained in the ,manner heretofore attempted without apparatus of the:most costly character. Preheating the air by 'means of the heat derived from the hot clinker, as it discharges from the kiln has not been found feasible; the air is not heated to the prope'r temperature, and frequently steam is thereby introduced with the air into the kiln, for the reason that the hot clinker is usually treated with a spray of water soonafter its exit from the kiln to assist in cooling and to brine; about a certain degree of hydration of the free lime and the calcium sulfate. Owing to "its high specific heat, .steam entering the kiln in this V manner tends to reduce the flame tempera ture. In other cases recuperators or stoves have been placedin the stacks of the kilns in order to make use of the waste heat of the escaping kiln gases. With short kilns, that is tosay, those of a length of to 6 0 feet, the temperature of the stack gases is sufiicien'tly high to secure some degree of preheat for the air, but with the longer kilns, such as 'a'reeoniing into ext nsive use at the present time, thetemperature ef'the esca ing gases is so low that the air sup lied threug-h seen regeueraters or recuperators does netacquire a temperature suthcient to effect a lar e output at cement. v

My ni'venti'en' overcomes the difieriities the airin arapid'anii etfec'tive'rnanner to any desired temperature, and therefore enables me to secure the very high temperature required for an output of cement cf come mereial importance.

producer and cement kiln of the unitary rotary inclined type ad'apted'to feed cement material downwardly therethrough as a traveling stream along its bottom, of a pre is to say, is heated by some source of heat external to that supplied to or by the kiln or to or by its discharging products.

. In order to make my invention better unders'tood, I shall make reference to the accompanying drawii'i'gs, forming a part of this specification, and in which and a preheating stove connected to a cement kiln, only the lower, portion of the latter being shown. Fig. 2 illustrates the method of ad.- rnitting the air and gas to the kiln.

Like reference characters denote like parts in the two figures. e

In the drawings, 1 'is a cement kiln having a hood 2 closing its lower end.

3 is'a gas producer having a fuel hopper 4, the blower or injector 5 provided with the jet 6, and the blast-distributing rip-take and hood 7. a

8 is an outlet for the combustible gas.

9 is a conduit or discharge terminating in blower which supplies air to the heating stove which is externally fired, that Figure 1 shows in section a gas producer,

the aperture 10 in the hood 2 and diseharg above cited, and permits of the heatingdi It consists in the combination witha-g-as iii port' 18 which is an armular' opening surrounding the gas discharge port 10.

19 is a ipe for supplying air, preferably compresse terminating in the center of the gai/lport.

' y method of operation is as follows: -A deep bed of. ignited coal or other fuel is builtup in the producerand a blast ofai or of alr and steam, or of air and roducts of. combustion, is introduced by the lowerinto the fire. -The gas roducedby this draftcurrent in passing t rough the fire is with-' drawn at 8, traverses the-conduit 9, and discharges into thekiln at 10 still hot from the producer. A fire 'is started in the fire-box 12 of the stove 11, and the flame from this.

firebox, or the hot' gases tlierefrbm travel around the pipes 13 and then esca e to the stack. The fan 14 is put in operation and a current of air is forccf 13 which air isthereby heated to a high tem' perature. It thereupon depart-s through the assages 16 and 17 and discharges into the The-mixture is ignited by any suitable means, as for in- In around the incoming gas.

stance, by starting a wood fire in the lower end of the kiln prior to the introductionof the air and gas.

- be admitted through t e jet 19, and the jet may be directed so that the air discharging therefrom, entering the kiln at a high ve-v locity,-/will cause the flame to impinge upon the cement, material. Under these conditions, combustion of the gas is veryvrapid and Ya White flame of intensely high tempera? ture develops around the cement material, rapidly transforming it into clinker. The higher the temperatureof the incoming air,

, the more intense will be the combustion and the. more rapidly the material may be fed downwardly throughthe kiln. Thus it is possible by having air of a sufficiently high temperature to rotate the kiln very rapidly andsecure a very large output. This has notbeen possible heretofore for the reason that the methods of preheating employed were such as to. make it impossible to bring theair to the high temperature required for ra idcombustion. The pressure under 'ch roducer gas is ordinarily delivered to the riln is from one to three inches of Water, and this is not suflicient to drive the flame forcibly into the kiln in such a manner that a clinkering temperature is produced some distance from the hood, and as a result the combustion by the older methods took place very close to the'front end of the kiln,

and consequently, clinkering took place almost at the time whenthe material was ready to discharge-from the kiln. Any irreguarities in the flame, and consequent.

fluctuations in temperature caused'the material to discharge in an underburned con dition. By my system of air and gas admixture the zone of clinkering is developed so wood or coal.

through the hot pipes Com ressed air may now fire-heated hot air to sald axia far up in the that the troubles hereto- ;fore experienced through fluctuations of the flame are. eliminated.

- The rotary inclined kiln shown is operated in the usual manner, comminuted raw cement material being introduced at its up .er'end (not shown) and the finished clin er discharged at its lower end through a suitable duct in the hood, the material traveling between these'points as a continuous stream onthe bottom and lower ascending quadrant 'of' the kiln in. the usual manner. I

"action of the iire.

Vlhile I have stated that cast iron pipe is to be preferred for the purposes of this invention, it is to be understood that tubes or lines of refractory material may be employed.

Forvery high temperatures such materials are in fact preferable, and it is possible to use a metal pipe for heating the air to a certain temperature, and .tofinishthe preheating by passage through dues of refractory material. The air for supporting combustion inthe kiln may by my system be first heated to up.-

ward of 400 F. by passage-through a recu'perat-or or stove placed in the kiln stack or housing and may then be conducted. through heat insulated passages to the se ar'atelvfired'st'ove, there being given the nal high j degree of heat-required. n stack stove is a very satisfactory means for accomphshmg the clinker (lischargingi'ron1 the lower end of the kiln also affords a source of waste heat which may be used for the pur ose'.-

By taking the gas st 1 hot from the producer. and burning it with very hot air, the necessary high clinkering temperature may first stage of preheating, although the hot be cheaply furnished in the rotary cement" kiln without use of comparatively costly concentrated fuels like powdered coal.

Having now described my invention and shown in what manner it may be erformed,

\what I claim and desire-to secure y Letters Patent is:

1. Apparatus for. burning cement comprising a rotary inclined cement kiln adapted to maintain a continuous downwardly traveling stream of cement material therethrough, a

gas producer, a pipe connection directly dis" charging hot gas therefrom axially in the'. kiln, and means for supplyinfia sheath of I y introduced gas for the purpose of burning the same. v U 2. Apparatus for burning cement compris- "ing a rotary inclined cement kiln adapted to maintain a, continuous downwardly travel ing stream of cement material the'rethrough, a gas producer, a pie connection directly -discharging hot gas til kiln, and means for sup lying a sheath of hot ereirorn axially in the air-to said axially intro uced gas for the purposeol burning the same, said means comprising a fire-heatecl stove for heating the air.

' 3..'Apparatus for burning cement comprising a rotary inclinedcement kiln adapted to maintain a continuous downwardly travelmg stream of cement material therethrough,

gas producer, apip'e connection directly discharging hot *gas" therefrom anially'in thekiln, and means for supplyin a sheath of fire-heated hot air to said ax-ia yzintrod'uced gas for the purpose of burnihg'the same, and means for transporting the resultant flame to a point beyond the mouth of ,kiln and for guiding its direction. Y j

' 4. Apparatus-for burning cement comprising a rotary inclined cement kiln adapted to .maintain a. continuous downwardly travel- 'lng stream of cement mater al therethrough,

a gas producer, a pipe connection vdirectly discharging hot gas therefrom aXiallyin the kiln, and means for supplying a sheath of hot airto said axially introduced gas for the purpose of burning the same, and means for transporting the resultant flame to apoint beyond the mouth of kiln andfor guidingits 6. Apparatus for burning cement comprisinga rotary inclined cement kiln adapted to maintain a continuous downwardly traveling stream of cement material therethrengh, v

lame to adistance from the a closing'hood for the lower end, apipecon- .nection therethrough adapted to introduce.

a jet of gas axially of the kiln, a concentric pipe adapted to furnish asheath of hot air aroundsaid jet, means for delivering hot air to 'the concentric pipe, such means comprising an externally heatedstove, and means for furnishing a jet of compressed air axially oi the gas jet to direct the flame.

7. Apparatus for burning cement comprising a rotary 'inclined kiln adapted to mainstream of cement material therethrough, a

'taina continuous downwardly traveling hood for the lowerend of the kiln, a gas producer, a pipe connection discharging gas through a circular port in thahood, an air preheating stove separately fired and a pipe connection taking air from the heater and discharging the same annularly around the gasport.

8. Apparatus for burning cement comprising a rotaryinclined-kiln adapted to 'main tain a continuous downwardly traveling stream of cement material therethrough, a 'gasproducer, an an preheat g stove, means for introducing the air andg'as'into the kiln to form flame, and means for carryingsaid 9. 'App'aratusfor burning cement comprising a rotary inclined adapted to maintain a continuously downwardly traveling stream of cement material therethrough, a gas producer, means for" feeding gas hot from the producer. into the mouth of said kiln, means for'iire-heating air, means for. introducing such fire-heated air as an envegvoping-sheath around the hot gas entering the kiln, and means for introducing a directing jet of airaxially of the body of -hot gas.

- Signed at New York, inlthe "county of New York, and State of New York, this 10th day of Nov. A; a

D. 1905. V HENRY L. DOHERTY. .Witnessesr i CARLETON ELLrs,

Ftnronnn P! 800mm.

,mouth of the f 

